Art of forming dies



Jan. 21, 1936.-

A. E. CARLISS ART OF FORMING DIES Original Filed May 18, 1934 31Min/mm1 Patented Jan. 2l., 1936 UNITED STATES yPATENT OFFICE ART oF FoRMiNG nnssV Original application May 18, 1934, Serial No.

726,416. Divided and this application November 16, 1934, Serial No. 753,402

5 Claims. (Cl. 'i6-101) In the art of forming dies wherein the die proper appears at the end of a tube, it has not heretofore been practicable to readily provide Y cle-arance at the inner or rear portion of the die 5 to prevent binding, resistance, and interference with the completion of the thread to be formed by the die.

The present invention relates to the art of forming dies of this type, and has as its essential object the provision of improvements in the art whereby the needed clearance will be afforded.

A further object in view is the effective accomplishment of this result in a facile, inexpensive, and accurate manner. 15 With these and further objects in view, the invention includes the steps for producing die teeth carrying prongs on a hollow cylinder or tube so located as to afford enlarging clearance inward beyond the die as distinguished from the lessening clearance of previous dies of this character.

The invention also comprises the art of forming such a die including the step of twisting or bending the prongs to the desired relation and subsequently hardening the finished article.

In tire valve stem treating tools it has heretofore been the practice to provide a tube or hollow cylinder having cutaway portions and threaded segments producing a die for straightening up injured parts of the external thread of such a valve stem. Such dies, however, have presented a diiiiculty of having less and less clearance inward of the die instead of greater clearance. This has been due largely to the fact that the die is formed by tapping out the end portion of the hollow cylinder which results in providing a constricting of the inner portions of the threaded parts. It is an object of the present improved art to overcome this difficulty and so construct 40 the die as to eliminate the inner constriction,

and to provide ample clearance as the work progresses inward along the die.

It is also an object of the present invention to so produce a die of this type yas to insure provi- 45 sion of clearance toward the trailing edges of the die segments or sections, that is in the direction opposite the direction of rotation.

In the accompanying drawing,-

Figure 1 isl a view in side elevation of a tool embodying the features of the present invention.

Figure 2 is an end view thereof .looking from beneath.

Figure 3 is a vertical section taken 'therethrough on the plane indicated by line 3-3 of Figure 2,

Since the present improved art of forming a die can be well illustrated and perhaps best described with reference to a specific embodiment of die, a product of the present improved die forming art is shown in the accompanying drawing in which I indicates a hollow cylinder or tubular section transversely through which is extended the pin 2 that is anchored in the cylinder I in any appropriate manner, as by being wedged therein. The pin 2 has at one end the screw-driver slot 3- for receiving the projection or cross-piece of the sleeve nut of a valve insides for screwing the same into or out of place. The opposite endV portion of the pin 2 is formed into a tap t proportioned to correspond with the threads on the inside of a valve stem, so that the tap i m-ay be used for straightening up such threads if they become battered or otherwise injured.

The pin 2 serves as a handle for turning the cylinder I, and the cylinder E serves as a handle for turning the pin 2.

The cylinder l has at one end portion notches 5, 5, opening at the end and leaving segments or die sections or lands t, il, each formed with the die teeth or cutting threads l at its inner face. Each section 6 is first formed as an axially extending projection from the main body of the cylinder i in that alinement therewith originally possessed, but after the sections have been formed by the production of the notches 5 and have been appropriately tapped to produce the cutting teeth and before hardening, each of the sections or segments S is subjected to a centering stress sufcient to bend the several sections inward at their lower ends for at least a few thousandths of an inch, so that the lower portions of the said section will be nearer together than the upper portions, speaking of the tool as located in the position seen in Figures 1 and 2. To facilitate disclosure of the inclination thus given the several sections, the lines of the walls at the inner and outer surfaces of the cylinder i are shown extended in Figure 3 at 8, 8 and 9, 9. These lines 8 and 9, of course, are not part of the structure, but are employed to facilitate disclosure of measurements that are in actual practice so small as to be diflicult of ready disclosure in an ordinary drawing. The amount of inclination given to the several sections or i segments 6 is only sufficient to afford the requisite clearance at the upper portion of the die threads or teeth, so that, if the original diameter be say .318, the reduction at the lower extremity would be to about ,302, though, of

course, such variation in these proportions may be made as found desirable to aiford best results under any particular set of circumstances. Not only are the several sections or segments 6 tilted or bent inward to cause their lower extremities to approach nearer than other parts of the sections, but each is twisted angularly as shown in Figure 2, so that the advance edge 'I' in each instance is at a shorter distance from the axis of rotation than is its trailing edge 1". Thus, as the cutting teeth 'I act on material engaged there is constant clearance both' in the general direction of the length of the die which widens out upward and in the direction opposite the direction of rotation as it advances about the work which widens in radius, so that clogging and tendency toward resulting injury to the work is obviated.

The upper end of the tubular portion or cylinder I is reduced in diameter providing an annular shoulder Iii and an upstanding projection II, the upper end of which projection terminates in cutting teeth I2, i2. The periphery of the projection II is preferably serrated or provided with a milled edge I3. The shouldered portion I0, projection II, cutters l2, and milling i3 are all completed, of course, while the cylinder I and its various parts are in their soft condition. They are preferably formed of steel, and after being shaped as described the cylinder is hardened by any appropriate and well known hardening process to a condition of substantially the hardness of an average tap or die. Of course, the pin 2 is similarly hardened, and may be drivenlinto 'a driven fit condition in the opening I4 in the cylinder after the cylinder is hardened or the connection may be made in any other manner preferred. However, the die segments 6 must, of course, be carefully tempered to be able to withstand the work of a die and the tap 4 likewise tempered. It is also essential that the projection I I with its milling I3 be hardened similarly. When the parts have been thus prepared, a sleeve l5 is forced axially onto the projection I I and is proportioned with respect to the said projection such that the ribs or ridges of the milling I3 enter and groove their way into the material of the sleeve I5 which is thus locked against independent rotation, and is also effectively anchored against longitudinal withdrawal under all ordinary circumstances from engagement with the projection I I. The sleeve I5 is preferably of mild steel, but may be made of other materials, such as brass, when and as desired. The sleeve l5 has its bore I6 proportioned with respect to a valve stem such as to snugly receive and yet allow free movement of the valve stem in and out of the bore I6. Thus, the bore I6 serves with respect to the cutters I2 as a counterbore and as a guide to retain the tool in the proper relation to the valve stem when the cutters I2 are being rotated against the end of the valve stem to finish it off to provide an effective seat for a cap to be mounted thereon. This dressing of the end of the valve stem may be done under any circumstances where a snug fit is to be secured, but is particularly desirable where the cap to be applied to the valve stem itself contains an air valve and the joint between the cap and the valve stem is, therefore, not only to be sealed as by engagement of a rubber or other soft gasket but to be sealed against air leakage with a more or less permanent connection and a gasket interposed of harder materials, such as hard paper fiber, or other hard gasket material. The sleeve I5 is preferably provided with knurling II, I'F, to facilitate handling and the lighter rotating operations of the cylinder I.

To facilitate disclosure of details not otherwise readily seen by the naked eye, the parts are shown in the drawing on a scale several times enlarged over the size of the parts of the now conven tional and popular size of such a tool.

This application is a division of my co--pending 1 application filed May 18, 1984, Serial No. 726,416.

What is claimed is:-

1. In the art of forming a die, forming projections on a tube and forming die teeth on the projections, bending and twisting the projections to provide clearance, and then hardening the projections.

2. The artas claimed in claim 1 wherein the projections are formed by forming notches in the end of the tube.

3. The art as claimed in claim 1 wherein the projections are formed by forming notches in one end of the tube and the projections are shaped by being bent for causing their free end portions to lie closer together than the end portions of the projections integral with the tube.

4. The art of forming a die comprising forming projections on a tube, forming die teeth on the projections, twisting the projections to a position causing the advanced edges of the die teeth to be nearer the axis of rotation of the die than the trailing edges thereof, and hardening the projections.

5. The art of forming a die comprising forming projections on a tube, forming die teeth on the projections, shaping the projections to provide clearance, the shaping of the projections including bending them for bringing their free ends nearer together and twisting them for causing the advanced edges of the die teeth to be nearer the axis of rotation of the die than the trailing edges thereof, and hardening the projections.

ALBERT EDWARD CARLISS. 

